Flex-Fuel Hydrogen Reformer for IC Engines and Gas Turbines

Abstract

An on-board Flex-Fuel H.sub.2 reforming apparatus provides devices and the methods of operating these devices to produce H.sub.2 and CO from hydrocarbons and bio-fuels. One or more parallel autothermal reformers are used to convert the fuels into H.sub.2 over the Pt group metal catalysts without external heat and power. The produced reformate is then cooled and the dry gas is compressed and stored in vessels at a pressure between 1 to 100 atmospheres. For this system, the pressure of the storage vessels and the flow control curves are used directly to control the amount of the reformers' reformate output.

To improve thermal efficiency of a mobile vehicle or a distributed power generator, portion of the reformate from the storage vessels is used to mix with the primary fuels and air as part of a lean burn fuel mixture for the engine/gas turbine. Also, this on-board Flex-Fuel H.sub.2 reforming apparatus can provide H.sub.2 to regenerate the NO.sub.x and diesel particulate traps for diesel engines, and/or it can provide H.sub.2 for a mobile or a portable fuel cell power generator.

Claims

1): An on-board Flex-Fuel H.sub.2 Reforming apparatus provides devices comprising: a). Providing one or more parallel autothermal (ATR) reformers for producing H.sub.2 and CO from hydrocarbons and/or bio-fuels over supported and/or unsupported Pt group catalysts; b). Providing one automatic control system comprising a control computer and/or microprocessors, flow meters/controllers, valves, pumps, sensors and thermocouples; c). Providing a stream of the ATR reformer's inlet fuel mixture comprising at least one oxidant, at least one fuel and at least one water/steam, wherein the reactants are selected from the reactant supply group consisting of liquid fuel loop, gas fuel loop, water supply loop, air supply loop, water electrolyzer loop, exhaust gas recycle (EGR) loop, water recycle loop and reformate recycle loop; d). Reacting said stream of the inlet fuel mixture over said catalysts inside the ATR reformer to produce a reformate containing H.sub.2 and CO from said fuels, and simultaneously controlling said fuel mixture's O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios within a given range so that the maximum ATR reaction temperature is kept constantly below 1200° C.; e). Providing one or more vessels/manifolds for storing the condensed water for the reformers and also storing said dry reformate produced from the ATR reformers at a pressure between 1 to 100 atmospheres, which is used by the downstream IC engine, gas turbines and/or fuel cell devices; f). Providing one or more flow control curves for regulating each reactant's flow rate, the dry reformate composition and the total reformer's flow output by the pressure of said storage vessels.

2). The apparatus of claim 1, wherein each ATR reformer is capable of performing the following steps: (a). Receiving a stream of inlet fuel mixture consisting of water, one or more fuels and an O.sub.2 containing gas in a given range of O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios into the reformer's first CPO/SR reaction zone; (b). Reacting said inlet fuel mixture over the Pt group metal catalysts with a residence time <300 milliseconds (calculated at STP) in the first CPO/SR reaction zone; (c). Reacting further the fuel and reformate mixture from step (b) over the Pt group metal catalysts with a residence time <5 seconds in the second SR reaction zone; (d). Producing rapidly in steps (b) and (c) a reformate comprising steam, H.sub.2, CO, CO.sub.2, N.sub.2, O.sub.2 and unconverted fuels at a given temperatures between 150-1200° C. and a given pressure between 1 to 100 atmosphere, and (e). Feeding the produced reformate from step (d) into the reformer's third reaction zone with a residence time <100 seconds and converting portion of the feed water and CO into hydrogen with or without Pt group metal catalysts at a temperatures between 50-500° C.

3). The apparatus of claim 1, wherein a system comprising an on-board Flex-Fuel H.sub.2 Reforming Apparatus and an engine/gas turbine is used by itself as a driving device for automobile, lawn mower, fork lift truck, diesel truck, bus, train and motorcycle.

4). The apparatus of claim 1, wherein a system comprising a simplified on-board Flex-Fuel H.sub.2 Reforming Apparatus, which are shown in FIG. 2, FIG. 3, FIG. 4 and FIG. 5, and a lean burn engine/gas turbine is used by itself as a driving device for automobile, lawn mower, fork lift truck, diesel truck, bus, and motorcycle.

5). The apparatus of claim 1, wherein a system comprising an on-board Flex-Fuel H.sub.2 Reforming Apparatus, an engine/gas turbine, an electric generator and a battery bank are used to generate and store electricity as a stand alone distributed mobile or a stationary power station.

6). The apparatus of claim 1, wherein a system comprising a simplified on-board Flex-Fuel H.sub.2 Reforming Apparatus, which are shown in FIG. 2, FIG. 3, FIG. 4 and FIG. 5, an engine/gas turbine, an electric generator and a battery bank are used to generate and store electricity as a stand-alone distributed mobile or stationary power station.

7). The apparatus of claim 5, wherein a stand-alone distributed power station is used to power electric vehicles/equipments, such as automobile, lawn mower, truck, forklift truck, bus, train, motorcycle, portable industrial/household electrical equipments/devices, electric utility vehicle, battery charger and backup power.

8). The apparatus of claim 1, wherein one of the fuels selected from the group consist of natural gas, CNG, LPG, gasoline, methanol or bio-ethanol is exclusively used by the reformer to produce H.sub.2 and CO reformate as a reducing agent to regenerate NO.sub.x traps and/or diesel particulate filter for a diesel engine.

9). The apparatus of claim 1, wherein the pressure of the reformate in the storage vessels/manifolds is kept between 30 to 100 atmosphere, and said vessel pressure is used to start up/shut down the reformer, or to increase/decrease the total amount of the ATR's flow output according to the control curves.

10). The apparatus of claim 1, wherein reformate pressure of the storage vessel is used to regulate each reactant's flow rate according to the predefined control curve, and is therefore used to increase or decrease the total amount of the reformate output, which is produced by the ATR reformers with a specified dry reformate composition according to said O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios of said inlet fuel mixture.

11). The apparatus of claim 1, wherein said high pressure reformate in the storage vessels is used as a reducing gas to reduce the reformer's supported Pt group metal catalysts, or to regenerate catalysts in the catalytic converters, NO.sub.x traps and diesel particulate filters.

12). The apparatus of claim 1, wherein said high pressure reformate in the storage vessels is used to provide H.sub.2 to a mobile electric vehicle/device which is equipped with a solid oxide or proton exchange membrane fuel cell stack, or to provide H.sub.2 or H.sub.2 rich reformate directly to an IC engine/gas turbine.

13). The apparatus of claim 1, wherein said high pressure reformate in the storage vessels is used to provide reformate to a small IC engine/gas turbine, a fuel cell device and/or a catalytic combustor to supply both heat and power as an on-board Auxiliary Power Unit.

14). The apparatus of claim 1, wherein said Flex-Fuel ATR reformer is typically operated at a temperature between 650° to 1000° C., and is used to generate hot water and hot air in a downstream condenser as one part of a combined heat and power generator.

15). The apparatus of claim 1, wherein said supported and/or unsupported Pt group metal catalysts inside the ATR reformer contains the total Pt group metal loading of 0.1 to 2000 g/ft.sup.3 of the catalyst volume, and said the Pt group metal catalyst comprising one or more of Pt, Pd, Rh, Jr, Os, and/or Ru metals.

16). The apparatus of claim 1, wherein the fuels are any chemicals selected from one or more of the following compounds: C.sub.1-C.sub.16 hydrocarbons, methane, natural gas, methane hydrate, LPG, C.sub.1-C.sub.8 alcohols, vegetable oils, bio-ethanol, bio-diesel, bio-methane, the industrial waste or vent gas containing volatile organic compounds (i.e. VOC, mainly organic solvents), and any bio-fuels derived from biomass or from agriculture/industrial/animal wastes.

17). The apparatus of claim 1, wherein the the H.sub.2 produced by the electrolyzer is used to regenerate the NO.sub.x trap and/or diesel particulate filter.

18). The apparatus of claim 1, wherein the amount and the flow rate of the H.sub.2/O.sub.2 produced by the electrolyzer, which is controlled by the pressure of the reformate storage vessel and the control curves, can be used directly as the ATR reformer's only oxygen source for the purpose of increasing the % H.sub.2 in the ATR reformate.

19). The apparatus of claim 1, wherein said one or more flow control curves, which is/are used for regulating each reactant's flow rate, the dry reformate composition and the total reformer's flow output by the pressure of the storage vessels, comprising (a). A single point on a given control curve is supplying: i. A group of pre-calibrated and pre-stored set points for all flow meters/controllers, which is down loaded from the control computer and/or the microprocessors for the purpose of controlling each reactant's flow rate; ii. A specified reformer's inlet fuel mixture which is at a given O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios according to said set points; iii. A specified reformate dry gas composition which is produced by the reformer from said inlet fuel mixture and is stored in the storage vessels, and iv. A specified amount of the reformate output which is produced by the reformer at a given flow rate according to the location on the control curve; (b). Multiple points on the same control curve which are capable of producing a series of different flow outputs with the same dry reformate composition; (c). The pre-calibrated different control curves for other reformer's inlet fuel mixtures which are used to produce H.sub.2 and CO from different fuels or bio-fuels by the same reformer.

20). The apparatus of claim 1, wherein the control curve from the control computer/microprocessors provides the total % reformate output capacity from the ATR reformers as a function of said reformate pressure in the storage vessels and, in order to maintain said pressure between 30 to 100 atmosphere, said automatic control system would start up/increase the reformer's flow output when said pressure is low or shutdown/decrease the reformer output when said pressure is high.

21). The apparatus of claim 1, wherein various control curves for different O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios, which are pre-calibrated for a given fuel and/or for various fuels, are stored either in the control computer or in the PLC/microprocessor controller, and these control curves are used by the same said reformer to convert said given fuel or various said fuels into H.sub.2 and CO reformate.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0040] FIG. 1 is a schematic illustration of a general system comprising a Flex-Fuel H.sub.2 Reforming apparatus, an IC engine/gas turbine and an electric generator in accordance with an exemplary embodiment of the present invention.

[0041] FIG. 2 is a schematic illustration of a system comprising an alternate simplified Flex-Fuel H.sub.2 Reforming apparatus, a lean burn diesel engine and an electric generator in accordance with another exemplary embodiment of the present invention.

[0042] FIG. 3 is a schematic illustration of a system comprising an alternate simplified Flex-Fuel H.sub.2 Reforming apparatus, a lean burn IC engine and an electric generator in accordance with another exemplary embodiment of the present invention.

[0043] FIG. 4 is a schematic illustration of a system comprising an alternate simplified Flex-Fuel H.sub.2 Reforming apparatus, a gas turbine and an electric generator in accordance with another exemplary embodiment of the present invention.

[0044] FIG. 5 is a schematic illustration of a system comprising an alternate simplified Flex-Fuel H.sub.2 Reforming apparatus and a small utility IC engine in accordance with another exemplary embodiment of the present invention.

[0045] FIG. 6 is a schematic illustration of the shape of catalysts being used inside the Flex-Fuel H.sub.2 Reforming apparatus in accordance with the exemplary embodiment of the present invention.

[0046] FIG. 7 is a schematic illustration of the shape of catalysts being used inside the Flex-Fuel H.sub.2 Reforming apparatus in accordance with another exemplary embodiment of the present invention.

[0047] FIGS. 8A and 8B are the schematic illustrations of a large metallic catalyst being used inside the Flex-Fuel H.sub.2 Reforming apparatus in accordance with another exemplary embodiment of the present invention.

[0048] FIGS. 9A and 9B are the schematic illustrations of a system comprising a personal computer and a programmable logic controller in accordance with the exemplary embodiment of the present invention.

[0049] FIG. 10 is the illustration of a control curve showing the relationship between the % reformer output capacity as a function of the reformate's pressure in the storage vessels.

DETAILED DESCRIPTION OF THE INVENTION

Description of the Preferred Embodiments

[0050] Traditionally, large scale hydrogen is produced industrially by performing steam reforming (SR) reactions of hydrocarbons over the Ni/Al.sub.2O.sub.3 pellet catalyst, and the reformer is commercially operated at a low space velocity (typically at 2,000-8,000/hr) under steady state high pressure conditions. Therefore, to supply H.sub.2 to a mobile equipment or a distributed fuel cell power station, it is required to transport either liquid H.sub.2 or high pressure H.sub.2 gas from a long distance central plant and, then, store the H.sub.2 in the local high pressure tanks for the applications. However, a more convenient approach to supply H.sub.2 for these applications is to use a smaller distributed H.sub.2 reformer, which can produce H.sub.2 locally from various gaseous or liquid fuels. Since a mobile vehicle or a distributed fuel cell power station is typically operated on the power demand basis, an on-board or a distributed hydrogen reformer must be able to operate satisfactorily under frequent start-up, shutdown and other transient operating conditions.

[0051] Using the traditional H.sub.2 production technologies, several small reformers were designed in the 1970s to convert sulfur containing diesel oil into H.sub.2 for the phosphoric fuel cell application, and these reformers typically used metal oxide and/or Ni/Al.sub.2O.sub.3 pellet catalysts to perform the catalytic partial oxidation (CPO) and steam reforming (SR) reactions at a low space velocity. But, due to low catalytic activities at a slow space velocity, these reformers were generally bulky and they were not suitable to be used as an on-board reformer. An excellent summary of these hydrogen production technologies was written by G. Vocks (“Structured Catalysts and Reactors”, edited by Cybulski and Moulijn, Marcel Dekker, Inc. Page 179 (1998)), herein incorporated by reference.

[0052] During the development of a new compact reformer in early 1980s, several monolithic Pt group metal catalysts were found to be able to produce H.sub.2 and CO from a commercial sulfur containing #2 diesel oil at a very high space velocity. As shown in the DOE report (DE-AC-03-79-ET15383, September 1981), a new ATR reformer, which utilized several monolithic Pt/Pd CPO catalysts in the first reaction zone at a space velocity of 126,000/hr (18 milliseconds, calculated at 1 atm and 0° C.), can convert most of the fuels into H.sub.2 and CO and, then, the unconverted fuels can be converted in the subsequent Pt/Rh SR pellet catalysts in the second reaction zone at a space velocity of 6,500/hr (i.e. 550 ms). Furthermore, it was later demonstrated that, under proper steady state operating conditions, this new improved ATR reformer could also successfully produce H.sub.2 from diesel oil, gasoline, LPG and JP-4 fuels without coke formation.

[0053] As shown in Table 1, the total HC conversion of every fuel evaluated in these experiments was >=99% (dry basis), and the total % (H.sub.2 and CO) produced was >50% under the O.sub.2/C ratio of about 0.38 and H.sub.2O/C ratio of about 2.50. Therefore, it can be concluded from these tests that this improved compact ATR reformer, which utilizes the monolithic Pt group metal catalysts, can successfully be used to produce H.sub.2 from various hydrocarbon fuels under very high space velocity conditions.

[0054] The Pt group metal (pgm) catalysts used in these demonstration tests as described in Table 1 were prepared by impregnating first one or more of the Pt, Pd and/or Rh solutions at a given metal concentration into a thermally stabilized gama-Al.sub.2O.sub.3 washcoat powder, which had a surface area between 50 and 600 m.sup.2/g. Here, the thermal stabilizers, which were used to maintain the surface area of the washcoat powder at high temperatures, comprise one or more oxides of lanthanum, cerium, praseodymium, rhenium, calcium, potassium, barium, yttrium, zirconium, strontium, magnesium and mixture thereof. Subsequently, the catalyzed washcoat powder was further coated on the surface of an inert monolith substrate, and then dried and calcined. The total combined metal content of each monolithic Pt group metal catalyst shown in Table 1 was typically between 0.10 to 2,000 g/ft.sup.3.

[0055] Though the inert monolith substrate used in Table 1 was a ceramic cordierite which had 200 to 600 straight channels per square inch (CPI), other suitable catalyst carriers can be a ceramic or metallic monolith, foam, plate, gauze, wire mesh, static mixer etc. Here, the ceramic monolith can be porous materials comprising one or more metal oxides selected from the group consisting of alumina, alumina-silica, alumina-silica-titania, mullite, cordierite, zirconia, zirconia-spinal, zirconia mullite, silicon carbide etc.; The metallic monolith can be a heat and oxidation resistant alloy such as Fecralloy, Kanthal, stainless steel etc.

TABLE-US-00001 TABLE 1 Summary of autothermal reforming of hydrocarbons over Pt group metal (pgm) catalysts (Hwang et al. AiChe Annual Meeting, Los Angeles Ca, Nov. 5, 2000) Hydrocarbon Jet Fuel No. 2 LPG LPG (JP-4) Diesel Run No. II-41 II-46 II-48 II-32 Catalyst CPO CPO-2B CPO-2B CPO-2B CPO-2B (pgm) (pgm) (pgm) (pgm) S.R. FP-34 FP-34 FP-34 FP-34 (pgm) (pgm) (pgm) (pgm) Condition H.sub.2O/C 2.430 2.480 2.280 2.570 O.sub.2/C 0.398 0.417 0.381 0.378 Temperature (C.) Inlet to CPO 749 749 749 749 S.R. TOP 865 896 921 942 S.R. MID 717 751 777 809 S.R. END 696 729 758 778 Dry Gas (%) H.sub.2 44.35 42.43 39.72 41.11 CO 9.94 10.09 12.49 11.52 CO.sub.2 12.19 12.17 12.18 12.51 N.sub.2 33.21 35.02 35.23 34.37 CH.sub.4 0.08 0.04 0.12 0.26 Equivalent H.sub.2 2.44 2.36 2.13 2.17 HC Conv. (%) 99.64 99.82 99.50 98.80

[0056] To produce hydrogen for fuel cell applications, U.S. Pat. No. 4,522,894 had concluded that the rates of partial oxidation reactions of diesel oil over the Pt group metal catalysts are much faster than that of the steam reforming reactions. In other words, at a the residence time <300 milliseconds, the % fuel conversion to make H.sub.2 and CO is primarily controlled by the O.sub.2/C ratio of the feed mixture with minor contribution from the H.sub.2O/C ratio. However, the related experimental studies as well as the thermodynamic calculations (DOE #DE-AC-03-79-ET15383 (1981) and DOE #DE-AC-21-79-MC12734 (1981)) had also concluded that the autothermal reforming process, as compared to the catalytic partial oxidation process, could widen the operating O.sub.2/C ratios without coke formation, reduce the reactor's peak temperature, extend catalyst durability, minimize the catalyst deactivation and achieve longer reformer life. In other words, the autothermal reforming process is practically a better and a preferred process over the catalytic partial oxidation process for a compact durable reformer. For this reason, the patented on-board reformers developed in the 1970s can be improved for its durability and the operation life by replacing the CPO reforming process with the ATR reforming process over the more advanced Pt group reforming catalysts, and this new improved Flex-Fuel H.sub.2 Reforming apparatus can be an effective and efficient on-board H.sub.2 reforming apparatus for a mobile vehicle.

[0057] In the late 1990s, a small commercial reformer, which can convert all HC fuels with long durability at a space velocity at about 54,000/hr (i.e. about 67 ms at STP), was developed for a Proton Exchange Membrane fuel cell (PEMFC) electric generator. In this study, a new generation of advanced reforming catalysts and a revised compact ATR reformer design were developed for producing H.sub.2 from natural gas and LPG. Briefly, a series of layered monolithic CPO/SR catalysts were developed to improve the steam reforming activities in the ATR reformer's first reaction zone. For these layered catalysts, a thin layer of the SR catalyst was first coated on the inert monolith surface and another layer of the CPO catalyst was then coated on top of the SR catalyst layer. With the intimate contact between these two catalyst layers, the heat producing CPO layer would generate and quickly provide the reaction heat for the endothermic SR layer without any heat transfer barriers. As shown in the U.S. Pat. Nos. 6,436,363 and 6,849,572, these new advanced catalysts, which were prepared with various multiple layered and/or with various metal gradient coating techniques, could achieve the most efficient utilization of the Pt group metals, could further improve the methane conversion, could reduce the reformer's volume, could reduce the reactor's peak temperature by about 50° C. and most importantly could provide a reformer with longer life without coke formation.

[0058] Using these advanced reforming catalysts, an improved smaller ATR reformer can be re-designed to produce H.sub.2 from various hydrocarbons and/or bio-fuels as an on-board reforming unit. For example, a compact and an economic ATR reformer for a mobile equipment can utilize only the CPO/SR catalysts in the first reaction zone without using the SR and WGS catalysts in the second and third reaction zones. This reformer will convert portion of the fuels into H.sub.2 and CO, and the remaining unconverted fuels and CO can be combusted by a downstream engine/gas turbine. However, for a stationary distributed power generator or for a small potable hydrogen station, the design and the operating conditions of an ATR reformer must be adjusted to produce maximum % H.sub.2 and minimum % CO in the reformate. In this case, the ATR reformer should rely on the CPO/SR and SR catalysts in the first two reaction zones to convert all (i.e. 100%) of the fuels into H.sub.2 and CO and, then, rely on the subsequent WGS catalyst in the third reaction zone to convert CO and H.sub.2O into H.sub.2.

[0059] For this on-board Flex-Fuel H.sub.2 Reforming apparatus, portion of the electricity generated by the electric generator as shown in FIG. 1 can be used by the water electrolyzer to produce pure O.sub.2 and H.sub.2. The produced H.sub.2 can be used to heat up catalysts above the light-off temperatures and, thus, can rapidly initiate the CPO reactions of fuels during the start-up period; The produced O.sub.2 can be used to increase the O.sub.2 content in the recycled exhaust gas, can be used alone as an ATR's oxidant or can be used to enrich the combined ATR inlet fuel stream mixture to >10% O.sub.2.

[0060] U.S. Pat. No. 5,648,582, herein incorporated by references, described a process of using a millisecond (ms) reactor to produce synthesis gas successfully from methane over a metal supported catalyst at a very short residence time (SV=800,000 to 120,000/hr, or about 3 ms). Here, air and/or pure O.sub.2 were used as oxidants for the CPO reaction, and the catalysts used in this millisecond reactor system were one or more of Rh, Ni, and Pt catalysts which were coated on the surface of a ceramic foam substrate, metal gauze or extrudate. Since 1990s, professor Schmidt and his group had successfully produced synthesis gas and olefins over mostly the ceramic Rh foam catalysts at millisecond contact time from methane, n-hexadecane, n-decane, JP-8, gasoline, diesel oil, ethanol, glycerol, vegetable oil, biodiesel, other volatile and non-volatile liquids etc. Several excellent patents and scientific papers have been published by this group in the last two decades. Overall, their studies have demonstrated that the volatile hydrocarbons and bio-fuels can easily be reformed catalytically into H.sub.2, CO and olefins with high yields in an millisecond reactor system, and that the synthesis gas can be produced from various fuels by either catalytic partial oxidation or autothermal reforming reactions over the Rh containing catalysts, which were coated on gauzes, ceramic foams or Al.sub.2O.sub.3 spheres.

[0061] In the last two decades, a group at Argonne National Laboratory has also done some excellent studies in developing catalysts as well as developing the advanced CPO and autothermal reforming processes. For example, U.S. Pat. No. 6,110,861, herein incorporated by references, described a newly developed two-part catalyst (i.e. 1% Pt/CeGdO pellet catalyst) which could effectively produce H.sub.2 from gasoline/natural gas, water and oxygen fuel mixture with the residence time of 0.1 to 2 seconds; U.S. Pat. No. 6,713,040, herein incorporated by references, described the detailed design and operating procedure for a compact autothermal reformer to produce H.sub.2 from fuels for the fuel cell application. Overall, the studies by this group had also demonstrated that H.sub.2 could efficiently be produced from iso-Octane, cyclohexane, 2-pentene, ethanol, methanol, methane and other fuels over the newly developed Pt containing two-part catalyst by the autothermal reforming process.

[0062] Since 2000, a lot of excellent patents and scientific papers have been published by various groups worldwide on the catalytic partial oxidation and the autothermal reforming processes, and it is impossible to cite every study here. However, it is clear from these publications that the CPO and the ATR processes can effectively be used to produce H.sub.2 and/or synthetic gas catalytically from various volatile hydrocarbons and bio-fuels under very high space velocity conditions (i.e. small reformer).

[0063] For industrial applications, the addition of water/steam to the reformer's inlet fuel mixture will convert a CPO reformer into an ATR reformer, and this ATR reformer which utilizes the advanced reforming catalysts can effectively be operated under wider range of the O.sub.2/C ratios without coke formation as a stationary H.sub.2 reforming apparatus. Furthermore, to improve over this stationary H.sub.2 reforming apparatus for mobile applications, an on-board Flex-Fuel H.sub.2 reforming apparatus, which provides several practical devices and the method of operating these devices without external heat and electrical sources, can produce H.sub.2 from various volatile hydrocarbons and/or bio-fuels for the IC engines/gas turbines.

[0064] Though most of the current gasoline IC engines are designed to operate stoichiometrically, the lean burn gasoline and/or diesel truck engines are becoming more popular in recent years. Since the lean burn IC engines will produce more NO.sub.x pollutant as compared to an engine running with a stoichiometric air/fuel mixture, a monolithic NO.sub.x trap is installed in the exhaust pipe to reduce the NO.sub.x emission from a lean burn gasoline engine. Similarly, a NO.sub.x trap and a diesel particulate filter are installed in the exhaust line to remove emissions from a lean burn diesel engine.

[0065] Typically, a NO.sub.x trap and a diesel particulate filter comprise some trap materials supported on a porous ceramic monolith, and the trap materials comprise a small % Pt group metals supported on an Al.sub.2O.sub.3 powder and one or more oxides of K, Na, Cs, Ba, La, Sr, Ca, Mg, Zn, Ce, Zr and the mixture thereof. However, each trap material has its own storage capacity, and it will not reduce the NO.sub.x or diesel particulate emissions once it is saturated. Therefore, these trap materials are required to be regenerated periodically by using an external reducing H.sub.2 and/or CO gases, and the Flex-fuel H.sub.2 Reforming apparatus can effectively produce this reducing gas for this application.

[0066] The IC engine/gas turbine can be started manually from room temperature to generate the hot exhaust gas, which is recycled back to heat up the ATR reformer and also to drive the electric generator to power up the PLC/ECU and all sensor/controllers. Once the electricity is generated, the whole system can be switched to the automatic operating mode and let the computer system operate the H.sub.2 reforming apparatus automatically.

[0067] The combination of this Flex-Fuel H.sub.2 Reforming apparatus and an IC engine/turbine can be used by itself as a driving device for a mobile device/equipment, such as lawn mower, chainsaw, motorcycle, fork lift truck, automobile, bus, truck and train; The combination of this Flex-Fuel H.sub.2 Reforming apparatus, an IC engine/turbine, an electric generator and a battery bank can be a useful distributed and integrated electric generating system for an electric car, truck, train, motorcycle, forklift truck, electric utility vehicles, battery charger, backup power generator, and other stationary or mobile electric equipment/devices.

Exemplary Embodiments Described

[0068] The on-board Catalytic EGR oxidizer described in U.S. Pat. No. 8,061,120 teaches a process of producing H.sub.2 and CO from various hydrocarbons and bio-fuels for the IC engines/gas turbines. To be a successful and durable reformer without coke formation and without catalyst deactivation and/or melting, the ATR reformer's reaction temperatures must be kept constantly <1200° C. (preferably <1000° C.), and the O.sub.2/C ratio of the reformer's inlet fuel mixture must be kept between 0.15 to 1.50, the H.sub.2O/C ration between 0.05 to 10.0 and the CO.sub.2/C ratio between 0.00 to 0.50. To improve over this Catalytic EGR Oxidizer, an on-board Flex-Fuel Hydrogen Reforming apparatus as shown in FIG. 1 is designed, and this on-board raforming apparatus can provide practical devices and the method of operating these devices primarily for mobile vehicles and/or distributed electrical generators where external power and water sources are limited. Furthermore, using the teachings of the present invention, potential simplified on-board Flex-Fuel H.sub.2 Reforming apparatuss and/or other various system configurations are available to one skilled in the art and, as examples, several simplified Flex-Fuel H.sub.2 Reforming apparatuss are included here for various specific applications.

[0069] Contrary to a steady state fuel cell reformer, a successfully on-board reformer must be able to convert fuels into H.sub.2 without coke formation under rapid transient (i.e. fast acceleration/deceleration), frequent start-up/shut down, steady state and other unsteady state operating conditions. Also, it must be able to perform autothermal reforming without any external power and water source, and the reformers must be able to be re-started very quickly with the system's own heat and electricity. Therefore, this Flex-fuel H.sub.2 Reforming apparatus is designed to provide several reactant supply paths (loops) for injecting the necessary reactants into an ATR reformer. Here, the reactant supply paths include a water loop, a gaseous fuel loop, a liquid fuel loop, a water electrolyzer loop, a recycle water loop, a recycle reformate loop, a recycle exhaust gas loop, and two air supply loops. Briefly, the controlled amount of at least one fuel, one oxidant and one water/steam from the reactant supply loops are injected into the ATR reformers for converting the fuels over the Pt group metal catalysts into a reformate containing H.sub.2 and CO. The produced reformate will be cooled, the condensed water will be recycled as one of the ATR reactant and the dry gas will be compressed and stored in one or more high pressure storage vessels. As described previously, the pressure of the reformate in the storage vessel is the primary feedback signal which is used to regulate the flow rate of each reactant according to the predefined control curve. Thus, this pressure signal is used to increase or decrease the total amount of the reformate output produced by the ATR reformers, so that the reformate pressure in the storage tanks can be maintain between 30 to 100 atmospheres. In other words, as the pressure of the stored vessels decreases, each reactant's flow rate, while keeping under the same O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios, will be proportionally increased and more reformate with the same gas composition will be produced by the reformer to keep the vessels' pressure within the limits. However, when the pressure is closer to 100 atmosphere, one or more ATR reformers will be operated at a reduced flow capacity, stayed in the idle mode or even shut down to decrease the total amount of reformate output to the storage vessels. Due to the fact that the ATR reformers may get shut down during the operation, it is very important that the reformers can be re-started very quickly with the system's own heat and electricity. Furthermore, this Flex-Fuel reforming apparatus is typically operated at a temperature between 650° to 1000° C., and it can be used to generate hot water and hot air in a downstream condenser as one part of a combined heat and power generator.

[0070] To produce a H.sub.2 rich reformate, the ATR reformer's inlet fuel mixture is preferred to be controlled at O2/C<0.5. However, this fuel rich mixture is mostly combustible and potentially explosive, it is thus very important to use proper fuel injectors for each reformer and also to minimize the total amount of fuel mixture injected into a reformer, so that any damages caused by system malfunctions can safely be reduced. For these reasons, this on-board Flex-Fuel H.sub.2 reforming apparatus comprises one or more parallel ATR reformers instead of a single large reformer.

[0071] The dry reformate is compressed and stored in vessels #10 and #10B at a pressure between 30 to 100 atmosphere, and the reformate is then reduced by a regulator #55a to a lower pressure between 1 to 50 atmosphere in flow manifolds #10A or 10C. Here, the controlled amount of the reformate in manifold #10A (stream #217) and the secondary air (stream #208) are mixed with proper amount of primary fresh air (stream #218) and primary fuels (stream #201A) to become a lean fuel mixture at a lambda ratio between 1.01 to 1.80 for an engine/gas turbine #11 (i.e. Lambda ratio=[actual air/fuel ratio]/[stoichiometric air/fuel ratio]). Portion of the reformate (stream #214) in manifold #10C can be used as a reducing gas to regenerate the catalysts in the NO.sub.x and diesel particulate traps. It can also be recycled back as a reactant (stream #215) for rapid start-up of the reformers, and/or can be used to supply H.sub.2 (stream #216) to an on-board APU #11A. The APU unit will provide heat and electricity in a small remote area when the big diesel engine is not in operation.

[0072] The flow meter/controllers shown in FIG. 1 can be metering pumps, mass flow meters/controllers or automobiles' electronic fuel injectors. Since any one of these flow controllers can regulate precisely the flow rate of a given gaseous and/or liquid reactant according to the predefined set point, the combination of these flow meters/controllers can thus blend several pure gas and liquid components together by controlling each reactant flow rate at a given value. Thus, these controllers can provide the ATR inlet fuel mixture with the specified O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios according to the set point given to each flow controller by the control curve, which is stored in the computer control system. Furthermore, by downloading from the computer a new set point to a specific flow meter/controller, this flow meter/controller can quickly change the flow rate to a new value with excellent repeatability and reproducibility. In other words, the O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios and the total flow rates of the fuel mixture can be maintained and/or changed to a new value very quickly and precisely by this control system.

[0073] For this Flex-Fuel H.sub.2 reforming apparatus system as shown in an exemplary embodiment in FIG. 1, the water reactant loop is consisted of tank #1, metering pump #50, flow valve #51 and flow meter/controller #52; The gaseous fuel reactant loop is consisted of tank #2, pressure reducer #55a, flow valves #51 and flow meter/controllers #52; The liquid fuel reactant loop is consisted of tank #3, metering pump #50, valves 51 and flow meter/controllers #52; The water electrolyzer is consisted of electrolyzer #5, battery #4, gas filers #5A/#5B and flow valves #51; The water recycle loop is consisted of heat exchanger #7, gas/liquid separator #8, filter #54, metering pump #50 and flow valve #51; The reformate recycle loop is consisted of reformate manifold #10C, compressor #9, flow valve #55 and flow meter/controller #52; The exhaust gas recycle loop is consisted of tank #10E, filter #54, compressor #9, flow valve #55 and flow meter/controller #52; The air loop is consisted of a turbo charger #14, tank #10D, heat exchanger #7, flow valve #55 or #51 and flow meter/controllers #52. Also, another primary air input to the engine/gas turbine is the flow line #218, which consists of a throttle valve #70 and an air mass flow meter (not shown). Since this on-board Flex-Fuel H.sub.2 reforming apparatus is controlled and operated automatically by a computer and/or a programmable logic controller (PLC) #100, the valves and the flow meters/controllers installed in every reactant loop must be compatible with the computer's input/output interface modules. In other words, they must be able to be open, closed, regulated and/or controlled by the computer/PLC system.

[0074] The IC engine/gas turbine #11 can be started manually using the current automobile's ignition method. In other words, the engine is started with rich combustion using primary air from line #218 and either gaseous or liquid primary fuel in line #201A. Once the engine/gas turbine is started, the primary air and fuel flows are both regulated by the position of the throttle valve #70, which is determined by the driver's desire to control the vehicle's speed. Then, the engine/gas turbine will turn the electrical generator #12 to generate electricity and will supply power to the computer control system #100 and the battery banks #13/#4; The exhaust gas will turn the turbo charger #14 to provide secondary high pressure air for the engine/gas turbine (line #208) and the ATR reformer (line #210). Afterword, the exhaust gas #211 is split into two streams where stream #211A/#212 is recycled back to the reformer to provide heat, O.sub.2 and steam to the reformers, and stream #213 will again be split into streams #213A and #213B, so that the NO.sub.x and/or diesel particulate pollutants can be removed by traps #17. Note that a dual trap exhaust pipe system is provided in this system for ease of performing catalyst regeneration. After the traps, the exhaust gas will pass through a catalyst converter #15 and a muffler #16 before venting into atmosphere.

[0075] The injector #53 is a specially designed device which can handle the injections of the combustible fuel, water, oxidant and other reactants safely. This injector can combine all the reactants together into a single fuel stream before this fuel mixture is admitted into the first reaction zone in the ATR reformer #6. By properly controlling each reactant's flow rate individually and/or simultaneously to obtain the fuel mixture with the specified O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios, the fuels will be reformed into H.sub.2 and CO over the Pt group metal catalyst at a temperature <1200° C. and a pressure between 1 to 100 atmosphere. For performing safe reforming reactions, the ATR reformer is equipped with a thermocouples #56 and a wide band O.sub.2 sensor #53A to fine tune the O.sub.2/C ratio of the fuel mixture before the ATR's first reaction zone. Since the reaction temperature is strongly related to the total reaction heats as well as the O.sub.2/C ratio of the fuel mixture, thermocouples can be used effectively to fine tune the O.sub.2/C ratio by adjusting slightly the flow rate of the secondary air flow or primary fuel and H.sub.2 flow. Furthermore, to avoid catalyst deactivation, to have long catalyst life and to avoid coke formation, it is necessary to install several thermocouples inside and outside the reaction zones to monitor and to provide the feed-back information for controlling the O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios, and also to keep the reaction temperature constantly below 1200° C., preferably <1000° C.

[0076] The PLC/ECU microprocessor and/or the computer control system #100 is capable of operating the whole system automatically. For example, when the pedal is pressed or released by the driver, the position of the throttle valve #70 will response to the driver's desire to increase or decrease the engine speed, and it will increase or decrease the primarily air flow in stream #218 as measured by the air mass flow meter, and the primarily fuel flow in stream #201A. If the molar ratio of H.sub.2 flow in line #217 /fuel flow in line #201A and the molar ratio of secondary air flow in line #208/H.sub.2 flow in line #217 are respectively controlled at a given (constant) value, the position of the throttle valve and/or the air mass flow sensor will also determine the H.sub.2 flow rate in line #217 and the secondary air flow rate in line #208. Therefore, the position of the throttle valve will simultaneously determine the flow rates in lines #218, #201A, #217 and #208, and the combination of these flows should provide a lean fuel mixture for the engine/gas turbine at a lambda ratio between 1.01 to 1.80. However, when engine is required to be operated at high loads, the final fuel mixture must be adjusted from the lean side to the rich side to produce more engine power. In this case additional extra fuel from line #201A and extra H.sub.2 from line #217 can be injected into the engine.

[0077] Regardless of the engine/gas turbine's speed and load, the control strategy is to keep the ratio of H.sub.2 flow in line #217/fuel flow in line #201A at a given value between 0.05 to 0.95, and also keep the ratio of H.sub.2 flow in line #217/secondary air flow in line #208 at a given value, so that the addition of these H.sub.2 and secondary air flows to the original fuel mixture (i.e. fuel #201A and air #218) will change it from the stoichiometric (i.e. Lambda=1.00) into a lean burn mixture at a Lambda between 1.01 to 1.80 (for gasoline car). In this case, the higher the engine speed, the larger amount of H.sub.2 is required to be injected into an engine/gas turbine and, thus, the faster the pressure is decreased in tank #10. As the computer control system detects the decrease in the vessel pressure, it can quickly start up the reformers and/or increase the reactants' flow rates to produce more reformate, so that the pressure inside vessel #10 can be maintained between 30 to 100 atmosphere. Similarly, when the engine speed is decreased, less amount of H.sub.2 is required and the pressure in vessel #10 will be reduced at a slower rate, and the computer control system will then decrease the reactants' flow rates to reduce the amount of total reformate produced. In this case, one or more ATR reformers can either be shut down or be operating at a reduced capacity when the pressure is closer to the upper limit.

[0078] Contrarily to a steady state fuel cell H.sub.2 generator, an on-board H.sub.2 reforming apparatus will mostly be operated under transient operating conditions, and frequent acceleration and deceleration of a mobile vehicle will create sudden fluctuation in the hydrogen demand. In other words, during the operation, the ATR reformers will be shut down, will be performed at the various flow capacity and will be re-started frequently. Therefore, it is critical to be able to re-start the reformers rapidly without external sources of heat and electricity, so that the reformate pressure in the storage vessel can be maintained within the limits during the sudden acceleration period.

[0079] FIG. 2 shows an alternative simplified Flex-Fuel H.sub.2 reforming apparatus which is suitable to be combined with a lean burn diesel truck engine. For a long durable system without coke formation, a reformer would like to be operated under steady state condition and, thus, frequent changes in the flow rates, temperature, O.sub.2/C and H.sub.2O/C ratios should be avoided or minimized. Unfortunately, a diesel engine will constantly be operated under frequent start-up/shutdown, acceleration/deceleration and/or other unsteady state transient operating conditions. In addition, since the commercial diesel oil contains some unsaturated high molecular weight components, and since it is very difficult to vaporize these coke producing fuel components completely within a very short residence time (i.e. under high space velocity operating condition), a second lighter fuel is used in tank #2 for producing H.sub.2 without coke formation by the on-board reformer, and the commercial diesel oil in tank#3 is still the main fuel for the diesel truck engine. In this design, one of the fuels selected from the group consist of natural gas, CNG, LPG, gasoline, methanol or bio-ethanol is stored in tank #2, and this fuel is exclusively used by the reformer to produce H.sub.2 and CO reformate as a reducing agent for the diesel truck engines. However, for a natural gas truck engine, H.sub.2 can be produced from fuel quickly and it is not necessary to have dual fuel tanks.

[0080] The description of all other devices/equipments in FIG. 2 are the same as those described in FIG. 1, and the method of operating this simplified Flex-Fuel H.sub.2 reforming apparatus for the diesel engine is similar to the method described previously for FIG. 1.

[0081] FIG. 3 shows an alternate simplified Flex-Fuel H.sub.2 reforming apparatus for a lean burn IC engine which uses CNG (compressed natural gas), H.sub.2 rich reformate gas, LPG, gasoline, methanol, bio-ethanol or other light weight hydrocarbons as fuel. Because a lean burn engine will produce more NO.sub.x emission, it is necessary to provide H.sub.2 and CO from flow manifold #10C (stream #214) to regenerate periodically the NO.sub.x trap #17.

[0082] FIG. 4 shows a simplified Flex-Fuel Raforming apparatus for a gas turbine. Here, the reformate comprising higher % H.sub.2 and the primary fuel are used as the turbine fuel, and the ATR reformer can physically be integrated into the gas turbine as a single unit. In addition, pure O.sub.2 or enriched O.sub.2 gas can be used to replace air for the reforming process, so that the reformate contains higher % H.sub.2 with less % N.sub.2 for the IC engine, gas turbine and solid oxide and/or proton exchange membrane fuel cell devices. In this case, the amount and the flow rate of the H.sub.2/O.sub.2 generated by the electrolyzer is directly controlled by the pressure of the reformate storage tank and the control curves.

[0083] For a small and economic utility engine which uses natural gas, LPG, bio-ethanol or gasoline as fuel, a very simple H.sub.2 generating system without excess accessories is provided as shown in FIG. 5. Here, the fuel from tank #3 is split into two streams. Stream #201 is injected into the engine directly, and stream #202 will be reformed into H.sub.2 using air as oxidant. Also, the recycled exhaust gas is used to provide steam, heat and CO.sub.2 to the ATR reformer, but the amount of the % recycled exhaust gas and the condensed water must be controlled to avoid flooding the engine with the condensed water.

[0084] FIG. 6 and FIG. 7 describe the shape of the catalysts used in the reformer. For example, the ATR reformer comprising only the CPO/SR catalysts in the first reaction zone will typically have catalyst shape as shown in FIG. 6, and an reformer comprising catalysts in all three CPO/SR, SR and WGS reaction zones will have catalyst shape as shown in FIG. 7. Also shown in these figures, a back-up flame igniter E is installed before the first catalyst sample for the purpose of initiating the CPO reactions manually.

[0085] For a large round metallic monolith catalyst, it is very difficult to measure the fresh and the aged catalytic activities in the laboratory. Therefore, one single large metallic monolith catalyst is designed to consist a smaller catalyst core at the center, and a large annular catalyst core on the outside, as shown in FIG. 8A and FIG. 8B. The smaller catalyst core in the center is designed to be able to remove from the whole unit without destroying the outside annular core, so that its catalytic activity can be evaluated by a laboratory testing unit. This catalyst design is especially useful to determine if an aged or a regenerated catalyst is still effective in reducing the emissions, and also to measure the rate of the catalytic deactivation as a function of time on stream. If necessary, the smaller catalyst core can either be restored back into the same location or be replaced by an identical fresh one after laboratory activity evaluation.

[0086] FIG. 9B shows the brain of the whole control system and it is represented as FIG. 9A in FIGS. 1 through 5. Here, a programmable Logic Controller (PLC, D2-260CPU unit from www.automationdirect.com) is connected and communicated to a HP PC computer through a RS-232 or an Ethernet cable, and this CPU module can also communicated with several input/output interface modules. Here, the main computer control software of the whole system is installed in the PC, and the PC will download a group of pre-calibrated set points to the PLC, which in term will transmit the control signal to the proper I/O module and carry out the actual control actions by the controllers. In other words, Once the interface modules receive the control signals, they can control and monitor pumps, flow meters/controllers, valves, thermocouples, O.sub.2 sensor and other devices in the system. Similarly, each device's status and the sensors' signal can transmit to the PLC and the PC via the reverse signal paths.

[0087] FIG. 10 demonstrates one of the control curve which shows the total % reformate output from the ATR reformers as a function of the pressure in vessels #10 and #10B. Here, each point in the curve represents a complete group of pre-calibrated set points for all flow meters/controllers at the same specific O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios, and at a given total reformate output from the reformers. Typically, as a given group of set points is downloaded from the PC to the PLC, the PLC will transmit the pre-calibrated set point to each flow meter/controller in the system and adjust each reactant's flow rate accordingly. Therefore, by blending all the individual reactant flow together, the O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios of the reformers' inlet fuel mixture can be controlled at a specific value and, thus, can produce the reformate with the same gas composition. In other words, every point in this control curve can actually provide the fuel mixture and the reformate with the same composition, but at a different total flow rates. Similarly, the pre-calibrated control curves for other fuel mixtures with different O.sub.2/C, H.sub.2O/C and CO.sub.2/C ratios and various flow rates can also be provided. Therefore, the same reformer has the flexibility of being used to produce H.sub.2 and CO reformate from various fuels and/or bio-fuels.

[0088] For a smaller system, the functions of the PC and the PLC as shown in FIG. 10 can be replaced by a powerful microprocessor, or by a small PC with the necessary I/O modules installed. Therefore, the automatic operation of this system can be done easily by a single alternative powerful control device.

EXAMPLE

[0089] Several fully automatic laboratory reactor systems, which had adopted the similar control strategy as shown in FIG. 10, had been assembled in the past. The reactor systems were used either to produce hydrogen from hydrocarbons and/or bio-fuels, or to evaluate catalytic activities of the laboratory experimental catalysts. These systems were very easy to operate and very reliable for performing daily routine experiments for several years.

Example 1

[0090] A larger laboratory reactor system which had more I/O modules than the one shown in FIG. 10 was used to study the catalytic autothermal reforming of bio-ethanol for hydrogen production. Here, a Simatic S7-400 PLC, all interface modules and the step-7 communication software were purchased from Siemens, and were installed and assembled together with a laptop computer as the main control computer.

[0091] A custom master control program stored in the main laptop computer was written in visual Basic to run the whole reactor system automatically. To operate the laboratory reactor system, the operator pushed the start-up button, turned on the external power supply relays and initiated the control program to start the test. According to the procedures written in the master control program, the PC would download the pre-defined set points simultaneously to the mass flow meters, metering pumps and furnaces. It would then turn on the solenoid valves according the pre-determined sequence to blend the fuel mixture from the pure gas/liquid supply tanks and provided a given fuel mixture with the specified O.sub.2/C and H.sub.2O/C ratios to the ATR reformer. Subsequently, the control program could start heating the furnaces, and could control and monitor/record the reactor temperatures and gas compositions. In other words, the control system, just like a technician, could perform the complete test procedures and record the test results automatically according to the procedures written in the master control software.

TABLE-US-00002 TABLE 2 Autothermal Reforming of bio-Ethanol to Produce H.sub.2 (Hwang, 2006 NATPA Annual Conference, Newark, California, Jul. 29, 2006). Product Gas Volume %, (dry) H.sub.2 37.53 O.sub.2 0.00 N.sub.2 39.26 CH.sub.4 0.00 CO 7.52 CO.sub.2 16.58 C.sub.2H.sub.5OH 0.00

[0092] An Agilent's Micro GC (model: refinery gas analyzer) was used to analyze the inlet reactant and the product gas compositions; The catalyst used was a ceramic monolithic catalyst (400 CPI) containing 80 g/ft.sup.3 total metals (Pt/Pd/Rh/CeO.sub.2—Al.sub.2O.sub.3—ZrO.sub.2, 2/1/1 metal ratio), and the ethanol, water and air feed rates were 10.54, 22.50 and 23.57 moles/hr respectively (i.e. H.sub.2O/C=1.07; O.sub.2/C=2.34). The test results at the inlet temperature of 262° C. are shown in Table 2. Note that the complete 100% ethanol conversation was observed, and that the reactor was reliable for daily operation with excellent repeatability and test reproducibility.

Example 2

[0093] As shown in FIG. 10, a DL-260 CPU PLC with digital input, digital output, analog input, analog output, ethernet communication module and thermocouple interface modules were purchased from www.Automation Direct.com; In this simple and cheaper control system, the valves #51 are connected to the digital output module; The mass flow meters (Tylan mass flow meters from www.ebay.com) and one water metering pump (model QV-#RHOCKC from Fluid Metering Inc.) are connected to the analog output and also to the analog input modules, and several type K thermocouples are connected to the thermocouple module.

[0094] A small Acer ASPIRE ONE laptop computer running Window XP is used as a master computer. A master control software which is written in visual Basic is used to download flow controllers' set points, to open/close valves, to monitor/control reactor temperatures, to monitor/record the status of each device, to carry out the experimental sequences and the method of operating this Flex-Fuel H.sub.2 reforming apparatus automatically.

[0095] This PLC control system is configured by Directsoft software and it can communicate with the ACER PC via KEPDirect communication software (both software were purchased from Automationdirect.com). The KEPDirect communication software can actually operate the whole control system manually.